Design Flaw...
 

So I have a v1 and a v2 that are still working. I also have a v2 that went up in flames that is currently at Castle.

It is pretty obvious there is a design flaw in how the board sits in the case. Every Monster I have owned has had the fan plug break off after a race or two.

I was performing some routine maintenance on my car after a race this weekend in which the monsters performed FLAWLESSLY. However, when I took the case apart on both I noticed that there is a little chip thingy that was crushed on both of my Monsters. :surprised: It is obviously getting slammed around in the case. I am wondering if this is why the Monsters are failing.

Here are some pics. Both of these Monsters are working fine, but this chip obviously bothers me. It is the one with the 223d written on it. I hollowed out the bottom of the case and it has the padding in it, but it still doesn't seem to be enough to prevent the chip from slamming against the bottom of the case. I understand the v3s will have a little more clearance in the case.

Just some additional data for Castle.

http://i240.photobucket.com/albums/f...o/PA130271.jpg

http://i240.photobucket.com/albums/f...o/PA130273.jpg

That broken part is the main BEC switching coil. And yeah, it must be hitting the case pretty good to break off. You might want to take some 1/8" - 3/16" thick foam bits and apply them to the motor and power solder pads as a sort of standoff. Yeah, you shouldn't have to do this, but anything to keep these running, eh?

Brian is right with the foam. That is exactley what I did to mine. You can find pics of what I did here: http://www.rc-monster.com/forum/showthread.php?t=15249

I did the same thing to my v1 and it is still kicking...

There is foam in the bottom of the case. That was one of the first mods I did to it. The pressure is pushing it down through the foam.

I am going to dremmel out the bottom of the case some more and see if that helps. I am tempted to put the external BEC on it to be safe now.

Actually, using foam on the whole bottom does pad it, but still places pressure on the relatively sensitive brains components. I was referring to adding thick foam bit ONLY under the large motor/power solder pads. This would leave the rest of the PCB suspended and (hopefully) not touch.

I know what you mean and where you coming from so don't take this the wrong way but it's funny to hear people say that. For as long as I can remember now most in the BL world have done some kind of modification to there ESC's to run them in larger vehicles. Looks how many modded quarks just to keep them running cool.

I think at this point CC has it figured out. I would also imagine their having to mod or change the case in some way to remedy that issue as well.

anyone mount it on the side ?

maybe if you mount it so the load is spread across the whole mounting face, there wouldn't be much of an issue. The load would be supported by the edges instead of in the middle of the case.

This may be a design flaw in the MMM, but it is not the root cause of all the problems the MMM is having.

It doesn't explain the people (me included) who have had a V1 or V2 go poof right out of the box after setting up with receiver and never getting any road time.

I did a little research and it seems the batch of components Castle used in V1 and V2 had frequent occurrences where the physical casing of the individual surface mount components was made too thin. So, all that was needed was a little jarring (maybe weakened during shipping), or even a change of atmospheric pressure to cause the smoke to break through the thin shell. And we all know once the smoke leaves, no workie no more.

I used some fuel tubing around the edges of the case to hold the board up and keep it from hitting the bottom case. I also dremmeled it out pretty good. I basically just cut a piece of fuel tube and glued it vertically in the corners. It seems to be working pretty well.

Hopefully, the new versions will be out soon. I think these two I have are on their last leg.

also heatshrink the bullet plugs that are on the pcb, another possible problem if a dead short across the heatsink

Whaile your doing the heat shrink, bent the close heatsink fins away from the bullets.

Or just remove the bullets and solder wires directly to the PCB, but that will probably void the warranty...

Trying to avoid voiding the warrenty since we all know they will all go in for warrenty replacement before long. It seems like they are getting close to shipping the V3 so it's time to run the heck out of the V1's & V2's. Brake-em & get a new one.

I got my first MMM V2 today, probably the last unit from Mike as it's out of stock now. I've just finished soldering the connectors and programming with castle link. I noticed the tight connectors touching the casing. I bent the heat sink fins. I tried to test the heat sink against all the connectors with a multimeter, it turned out the heat sink is isolated from the circuit so even if any wire touches the heat sink, there would be no short. I also dismantled the switch and bent the rocker contact a little to have a tight contact. I tried to run it with 6-cell nimh with 7700 mamba motor on the table, no full throttle just about a third. I'll leave this on till the voltage on nimh goes down to 6 volts.

Ya it's coated with something but that coating will wear off over time with vibration etc. (at least mine is).

I scraped the coating for the test leads to have contact, still no reading.

http://i328.photobucket.com/albums/l...oy/MMMMOD7.jpg
This is from Lutach's picture.
I see now where the problem comes in: if any two of the connectors will touch the heat sink, a short can occur.

Eek! I'm glad I have a V1. IMO, that is unacceptable - too much of a risk there.

i believe this is why on the v3 the battery wires will be soldered directly to the pcb.

Exactly. The heatsink is mounted to the board using non-electrically conductive thermal epoxy, and the FETs it's mounted to do not have any exposed metal.

CC made a good change in V3 to have wires soldered to the battery side of the board.

And imagine if the 2 power wires short!
Brian, is the castle link included with the monster same as the regular castle link (for other mambas) that's sold separately? I do have the regular castle link for my sidewinder.

That's why I'm just waiting patiently until I see how the V3's are so I can send mine in to get it replaced.

Now your with me.:yes:

Castlelink is included with the MMM

Unfortunately, I wish they'd sell it for $10 cheaper and sell it without the Castle Link. I have 5 Castle Link set ups at the moment... 3 from 3 different MMM ESCs (all still working by the way :wink:), and 2 from 2 different 1/18 scale systems... :lol: Oh well, not really a big complaint... I can just sell them separately.

hi

- i sawed off the motorbullets very very carefully
- ream them so that there is no contact with the heatsink anymore
- removed the whole hardcase and small fan.
- put a bigger foam under the esc and a 40*40*20mm fan (feed in by the batteries not the bec) on the heastsink
- soldered the motorwires directly on the board
- disable the esc bec
- and shrunk the whole thing with a big heat shrink tube.

i'll see how it will hold up.

bye
rhylsadar

I was just thinking of ordering one of the v2s if I could get it cheap and pretty much de-casing it, switching fans and removing the switch. That SHOULD make it work. What do you think? I would still get a V3 if its good, but this would hold me over and be extremely cheap.

some pics. i still haven't used it yet. however programming with the castle link functioned ok.

http://www.jaeser.org/~beat/images/1...mamba_(17).jpg
http://www.jaeser.org/~beat/images/1...nstermamba.jpg
http://www.jaeser.org/~beat/images/1.../moddedmmm.jpg

i'll use a receiver battery or a UBEC. not sure yet.

bye
rhylsadar